Beryllium-aluminum (Be-Al) alloys are typically high modulus, low density alloys containing high levels of aluminum. For example, the most common Be-Al alloy, Lockalloy, a trademark of the Lockheed Corporation, comprises 62Be-38Al weight percent. Be-Al alloys were developed to combine the ductile properties of aluminum with the higher strength properties of beryllium. The specific light weight, high strength properties of Be-Al alloys make them particularly useful in applications where weight reduction provides significant cost benefits.
Metallic alloys that have tenacious oxides are difficult to join using conventional bonding methods. Be-Al alloys such as Lockalloy are particularly difficult to bond because of the oxides associated with both aluminum and beryllium. Furthermore, the bonding temperature for Be-Al alloys is limited because of the low melting point of aluminum, which remains separate from the beryllium because of low solubility of the elements. An Al-Si braze alloy, having a melting point of approximately 570.degree. C., is typically used for bonding aluminum alloys. When Al-Si braze alloy is used to bond Be-Al alloys, however, shear strengths of only about 25% of the parent alloy are achieved. Therefore, a need exists for a method of bonding Be-Al alloys with improved interface shear strength over that achieved by conventional brazing techniques.